FIG. 1 depicts a portion of a conventional energy assisted magnetic recording (EAMR) disk drive 10. The conventional EAMR disk drive 10 includes media 12, slider 14, laser 16, grating 18, and EAMR transducer 20. In operation, the EAMR transducer 20 receives light, or energy, from the conventional laser 16. More specifically, light from the laser 16 is coupled into the grating 18. A waveguide (not explicitly shown in FIG. 1) and, in some embodiments, a near field transducer (NFT) (also not shown) within the EAMR transducer 20 direct the light from the grating to the media 12. An optical spot 22 on the media 12 near the air-bearing surface (ABS) is thus developed. The energy delivered to the conventional media 12 through optical spot 22 heats a small region 24 of the conventional media 12. The region heated is known as the thermal spot 24. The conventional EAMR transducer 10 magnetically writes data within the thermal spot 24 by energizing the write pole (not shown) of the conventional EAMR transducer 20. The region of the conventional media 12 within the thermal spot 24 has a reduced coercivity due to its higher temperature. Therefore, the conventional EAMR transducer 20 may more easily write to the conventional media 12.
Although the conventional EAMR transducer 20 functions, there are drawbacks. Extending the conventional EAMR transducer to higher densities may be problematic due to the thermal spot 24 size. More specifically, the size of the thermal spot 24 may limit reductions in the track pitch. In order to write at higher densities, a smaller thermal spot is desired. Because the conventional media 12 typically includes lower thermal conductivity underlayers, the thermal spot 24 is typically larger than the optical spot 22. Thus an even smaller optical spot 22 is desired at higher densities. In order to obtain a smaller optical spot 22, optical components within the conventional EAMR transducer 20 must be shrunk. Fabrication of portions of the conventional EAMR transducer 20, such as the NFT (not shown), at such small sizes may be challenging. Consequently, shrinking the size of the optical spot 22 and thermal spot 24/24′ for higher density recording may be problematic. For conventional EAMR recording, a reduction in the track pitch with respect to thermal spot size may also adversely affect performance. If the spot size is greater than or equal to the track pitch, tracks may be significantly or completely erased. For example, FIG. 2 depicts a portion of the conventional media 12′ in which tracks 30, 32, and 34 are written. For each track 30, 32, and 34, the thermal spot 24′ is used for writing. The thermal spot 24′ has a diameter d. Cross-hatched thermal spots 24′ correspond to a magnetic field of one polarity (e.g. out of the plane of the page), while clear/white thermal spots 24′ correspond to a magnetic field of another polarity (e.g. into the plane of the page). For clarity, only two spots 24′ are labeled. The bits in each track 30, 32, 34 are written in the down track direction (vertically in FIG. 2). The track pitch is TP and less than the thermal spot diameter. A conventional squeeze write scheme is used. In this situation, the track 32 may be inadvertently overwritten by the heating in thermal spot 24′ for tracks 30 and 34. Further, techniques such as thermally insulating portions of the conventional media 12/12′ or using higher thermal conductivities have been used to achieve a smaller thermal spot size. However, such techniques require re-engineering of the media 12 and thus may have limited utility.
Accordingly, what is needed is a system and method for improving performance of an EAMR transducer, particularly at higher densities.